You may have used a Base app that let you swap, mint, or send without first buying ETH to cover the network fee. That is not a special exception to how Base works, it is a feature built on top of it, and it is worth understanding what is actually happening behind the scenes before you rely on it. This article covers how gasless transactions work, what a paymaster is, and where the tradeoffs sit.
Gas is never actually free
Every transaction on Base still needs to pay a fee to be included in a block, exactly as described in our gas fees on Base article. What changes with a gasless transaction is who pays that fee and what they pay it with, not whether a fee is paid at all. When an app markets a transaction as gasless, it means the app, a wallet provider, or some other third party has agreed to cover the ETH cost for you, usually under specific conditions they control. Understanding those conditions matters more than the word "gasless" itself.
Why this requires a smart wallet
Gasless transactions are only possible with a smart contract wallet, the kind covered in our smart wallets and passkeys article. A traditional wallet, known as an externally owned account, signs a transaction and sends it directly to the network with a fee attached from that same account's ETH balance. There is no step in between where someone else can step in and cover the cost.
A smart wallet works differently. Instead of submitting a transaction directly, it submits something called a UserOperation, a structured request that describes what you want to do. That UserOperation goes to a specialized network participant called a bundler, which packages it together with others and sends it to a shared onchain contract called the EntryPoint. The EntryPoint contract is what actually executes your request and pays the real network fee. This whole system is defined by a standard called ERC-4337, and the same EntryPoint contract is deployed at the same address across Base, Ethereum, and most other EVM networks, which is part of why it has been adopted so widely.
Where the paymaster fits in
A paymaster is a separate contract that sits inside this flow and tells the EntryPoint, in effect, "let this fee be paid by me instead of the user." It is a distinct, pluggable piece of the ERC-4337 system, which is why not every smart wallet or app offers one, and why the ones that do can set their own rules for when they apply.
In practice, paymasters on Base are used in a few different ways:
App-sponsored gas. An app covers the fee itself, often to remove friction for a specific action like a first transaction, a mint, or an onboarding flow. The app is effectively paying your network fee as a cost of acquiring or retaining you as a user.
Pay gas in a token other than ETH. Some paymasters let you pay the fee in a stablecoin like USDC instead of ETH. You are not skipping the fee, you are paying it in a different asset, with the paymaster handling the conversion.
Wallet-level sponsorship. Some wallet providers sponsor gas as a built-in feature for their users, within limits they set.
None of this changes what happens onchain. The transaction is still real, still final once confirmed, and still visible on a block explorer exactly as covered in our block explorer article. The only difference is which address the ETH left from.
What to actually pay attention to
A sponsored transaction is still a transaction, and the same fundamentals from our wallet signature requests article still apply. Removing the fee does not remove the need to read what you are approving. If anything, a "free" action can make people click through faster and pay less attention, which is exactly the moment scammers count on.
A few things are worth keeping in mind specifically because gas is sponsored:
Sponsorship is conditional, not permanent. An app that covers gas today can stop tomorrow, restrict it to certain actions, or cap how many sponsored transactions you get. There is no guarantee baked into the network that any given transaction will be free.
It is a business decision, not a network subsidy. Base itself is not waiving fees. Someone, usually the app or wallet provider, is paying real ETH to the network on your behalf, which means they have decided the transaction is worth covering.
Your smart wallet's rules still govern everything. Because a smart wallet is a program, its logic decides what it will and will not do, sponsored or not. The same due diligence questions from our smart contract article, about who wrote the code and how long it has been in use, still apply to the wallet itself.
Why this matters for onboarding
The main reason paymasters have caught on is straightforward: needing to already own ETH just to move your first token is a real barrier for anyone new to a network. Gasless transactions let a first-time user try an app, claim something, or make a small swap without first solving the separate problem of acquiring gas. That is a genuine usability improvement, and it is a large part of why account abstraction has been adopted across most major EVM chains rather than staying a Base-specific experiment.
It does not remove the underlying mechanics of the network, and it is not a reason to skip the basics. A gasless transaction on Base is still a real, final onchain action, paid for by someone, and worth reading carefully before you approve it.
If you would rather hold a straightforward wallet where you always know exactly what you are signing and what it costs, Simple Base Swap is a self-custody wallet built for exactly one network. Start at app.simplebaseswap.com, or grab the iOS or Android app.